Outcomes: Death from all causes, death due to bleeding, death due to multiorgan failure, death due to vascular occlusive events and non vascular occlusive events. Vascular occlusive events include: myocardial infarction, stroke, deep vein thrombosis and pulmonary embolism. All events were measured at 28 days or hospital discharge Interventions and comparisons: We will compare the effect of red cells transfusion versus no red cells transfusion. We will also evaluate the effect of the number of units of red cells transfusion.